My fiance and my 1998 yamaha warrior seems to get too much fuel...it backfires and when we are riding it and were going too slow we have to rev it up so that it doesnt load up with fuel....the guy that we got it off of said that it has a moose jet kit in it and thats why it gets too much fuel....but we took the carborator off and checked all the jets, the main jet thats on it is a 134 and stock is 145 and the pilet jet is 42.5 which is stock so we have no idea why its getting too much fuel...does anyone know?

 

Well, jet sizes are not standard. Everyone wants to do there own so a 134 in this case is not equivalent to 145. Backfiring is usually a symptom of too little fuel. Check the plug to see if white/lean or black/rich.

 

setting the low speed fuel screw under the front of the carb on the engine side.
turn till it seats then turn out two times start engine
with engine warmed up turn up throttle 10 to 20 %
what your trying to do is get the low throttle mixture correct
more than 1/2 a turn in you will need next smaller pilot jet
more than 3 turns out with out a difference in idle speed you will need a bigger pilot jet. you want to be within that range with the highest idle result by turning the fuel screw, if achieved turn idle back to normal and ride, if bike surges at 1/4 throttle turn fuel screw out 1/2 turn.thanks